Chlorambucil
Alkylating agents
Alkylating agentsHigh alert
An error with this medicine can cause serious harm: double checks and protocols are used.
A slow-acting oral nitrogen mustard, historically the classic drug for chronic lymphocytic leukaemia; still used when newer drugs are not available.
Quick facts
- Group
- Alkylating agents
- Target
- DNA (guanine N7), cross-linked by the mustard
- Used for
- Chronic lymphocytic leukaemia · Hodgkin lymphoma
- Key effects
- Gradual fall in white cells · Nausea and vomiting
- Monitor
- Blood counts regularly during treatment · Liver tests
- ATC
- L01AA02
No doses: the clinician sets them by the current guideline.
Mechanism of action
Chlorambucil is an aromatic nitrogen mustard. Its two chloroethyl arms form reactive aziridinium ions that bond to guanines on both DNA strands and cross-link them. Its effects on the bone marrow, lymphoid organs and epithelia are those of the other mustards, but it acts slowly and its oral dose can be titrated against blood counts.
- The chloroethyl arms form reactive aziridinium ions
- These bond to guanines and cross-link DNA
- Lymphocytes stop dividing and die
Indications
- Chronic lymphocytic leukaemia, when targeted drugs are not available or not tolerated, or for relapse. Chronic lymphocytic leukaemia →
- Some non-Hodgkin lymphomas. Non-Hodgkin lymphoma →
- Hodgkin lymphoma. Hodgkin lymphoma →
Adverse effects
Common
- Gradual fall in white cells and platelets
- Nausea and vomiting with larger single doses
- Mouth sores
- Irregular periods, low sperm counts
Contraindications
- Hypersensitivity to chlorambucil
Key interactions
- Other myelosuppressive drugs and radiotherapy
- Additive bone marrow suppression.
What is monitored
- Blood counts regularly during treatment
- Liver tests
- Neurological symptoms in people with seizure risk
Administration and safety
- Oral tablets; hazardous drug handled with gloves or clean hands.
- The dose is adjusted to blood counts; treatment may last months.
- Kept in the refrigerator in its original container, out of children's reach.
Pregnancy and breastfeeding
Can harm the fetus; reliable contraception is used during treatment.
Nursing care
- Ask about previous seizures or head injury before starting.
- Check counts and report bruising, black stools, fever or cough.
- Teaching: contraception; infertility can be permanent, so fertility preservation is discussed beforehand.
Pharmacokinetics
- Absorption
- Oral, adequate and reliable.
- Metabolism
- Hydrolysed to inactive products.
- Half-life
- About an hour and a half in plasma (G&G).
Test yourself
Think of the answer, then tap the question to see it.
Which leukaemia was chlorambucil classically used for?
Chronic lymphocytic leukaemia.
Which neurological adverse effect is linked to chlorambucil?
Seizures, a particular concern in people with a seizure history or head injury.
Why is chlorambucil easy to titrate?
It is oral and acts slowly, so the dose can be adjusted to the blood counts.
Connections
← Back to the class: Alkylating agents
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Chlorambucil: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.